Heller U.S. Pat. No. 4,567,882 discloses an endotracheal tube having a fiberoptic light conductor extending lengthwise through the transparent wall thereof. The conductor ends in a light-emitting terminus adjacent the tube's distal end, and light emitted laterally from the tip of the medical tube may be visually and externally observed through the body wall of a patient for accurately and quickly determining the anatomical location of that tip.
Other devices and methods for transillumination have been disclosed in the prior art. Schellberg U.S. Pat. No. 1,704,764 discloses transillumination through the wall of the colon by inserting a light bulb into a transparent catheter after the catheter is in place. Others have used bendable light wands or light-transmitting cables to aid in the placement of open-ended endotrachael tubes to guide the placement of such tubes by transillumination. See Vollmer, T. P. et al Annals of Emergency Medicine, Vol. 14, No. 4 (April 1985); Rayburn, R. L., Anaesthesia, Vol. 34, pp. 677-8 (1979); Foster, C. A., Anaesthesia, Vol. 32, p. 1038 (1977).
The use of stylets to guide the placement of catheters, especially tubes for the administration of parenteral fluids, is also well known. Anderson U.S. Pat. No. 4,244,362 discloses the use of a flexible stylet for guiding the placement of an endotrachael tube.
Other references indicating the state of the art are Smiddy U.S. Pat. No. 3,776,222 and DeLuca U.S. Pat. No. 4,096,862.
In some medical applications it is desirable to use a medical tube formed of relatively soft, highly-flexible material, especially where such a tube must contact delicate tissues or remain in place for extended periods. A nasogastric tube is one example; a peritoneal dialysis catheter is another. Medical tubes for evacuating fluids from the plural cavity, or tubes for subcutaneous abscess drainage, preferably have similar characteristics. Tubes intended for such uses generally have distal end portions with a plurality of side openings and are provided with transverse walls at their extreme distal ends so that the openings are less likely to become obstructed in use. Because of their relatively soft, floppy character, such tubes may be difficult to direct, advance, and position properly within the body without becoming twisted, folded, or kinked.
Accordingly, one aspect of this invention lies in recognizing that a fiberoptic light conductor may provide an ideal stiffening and torquing element for a relatively floppy medical tube if the light conductor extends substantially the full length of the tube, is coupled to the tube at its proximal end, and also preferably engages the inside surface of the tube at least at its distal end. The light conductor and tube therefore move together as a unit. This facilitates ease of positioning of the tube as both may be twisted or torqued in one motion. Not only does the fiberoptic light conductor add the requisite degree of stiffness and torquability to the tube to facilitate its directional control during insertion and placement, preventing undesirable kinking or independent twisting of the tube, but light may be transmitted through the conductor to its distal end for purposes of transillumination through the body wall of the patient. Light emanating from the end face or faces of the conductor passes through the distal end wall of the transparent medical tube and may be externally observed through the body wall of the patient as a spot of light. Following proper placement, of the medical tube, the light conductor is withdrawn from the medical tube through its open proximal end, and the tube is then utilized for the intended medical procedure.
Briefly, the combination of this invention takes the form of a transparent medical tube and a flexible fiberoptic light conductor slidably and removably disposed therein, the term "transparent" being used here to mean light transmissible and therefore including the use of materials that are not necessarily clear and may even be translucent. Coupling means are provided at the proximal ends of the tube and insertable light conductor to secure them together against independent relative rotation. With the light conductor removed from its lumen, the medical tube is highly flexible or floppy, being formed of soft thermoplastic material. The light conductor is flexible but relatively stiff in comparison with the medical tube. A smooth glass fiber, or a cylindrical bundle of such fibers for larger size tubes, is particularly effective. So that twisting or torquing forces may be transmitted from the light conductor to the medical tube during an insertion procedure, the light conductor should be dimensioned to fit closely but slidably within the lumen of the tube.
Other features, advantages, and objects will appear from the specification and drawings.